From: David Laight <David.Laight@ACULAB.COM>
To: 'Johannes Berg' <johannes@sipsolutions.net>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Cc: "nstange@suse.de" <nstange@suse.de>,
"ap420073@gmail.com" <ap420073@gmail.com>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"linux-wireless@vger.kernel.org" <linux-wireless@vger.kernel.org>,
"gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
"rafael@kernel.org" <rafael@kernel.org>
Subject: RE: [RFC] debugfs: protect against rmmod while files are open
Date: Fri, 9 Oct 2020 10:56:16 +0000 [thread overview]
Message-ID: <8fe62082d9774a1fb21894c27e140318@AcuMS.aculab.com> (raw)
In-Reply-To: <2a333c2a50c676c461c1e2da5847dd4024099909.camel@sipsolutions.net>
From: Johannes Berg
> Sent: 09 October 2020 11:48
>
> On Fri, 2020-10-09 at 12:41 +0200, Johannes Berg wrote:
>
> > If the fops doesn't have a release method, we don't even need
> > to keep a reference to the real_fops, we can just fops_put()
> > them already in debugfs remove, and a later full_proxy_release()
> > won't call anything anyway - this just crashed/UAFed because it
> > used real_fops, not because there was actually a (now invalid)
> > release() method.
>
> I actually implemented something a bit better than what I described - we
> never need a reference to the real_fops for the release method alone,
> and that means if the release method is in the kernel image, rather than
> a module, it can still be called.
>
> That together should reduce the ~117 places you changed in the large
> patchset to around a handful.
Is there an equivalent problem for normal cdev opens
in any modules?
David
-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
next prev parent reply other threads:[~2020-10-09 10:56 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-08 15:48 [PATCH net 000/117] net: avoid to remove module when its debugfs is being used Taehee Yoo
2020-10-08 15:59 ` David Laight
2020-10-08 16:14 ` Johannes Berg
2020-10-08 16:37 ` Taehee Yoo
2020-10-09 5:38 ` Nicolai Stange
2020-10-09 10:07 ` Taehee Yoo
2020-10-09 5:09 ` Nicolai Stange
2020-10-09 7:45 ` Johannes Berg
2020-10-09 10:15 ` Taehee Yoo
2020-10-09 10:21 ` Johannes Berg
2020-10-09 10:41 ` [RFC] debugfs: protect against rmmod while files are open Johannes Berg
2020-10-09 10:48 ` Johannes Berg
2020-10-09 10:56 ` David Laight [this message]
2020-10-09 10:56 ` Johannes Berg
2020-10-09 11:15 ` gregkh
2020-10-09 15:33 ` [PATCH net 000/117] net: avoid to remove module when its debugfs is being used Steve deRosier
2020-10-09 7:53 ` [CRAZY-RFF] debugfs: track open files and release on remove Johannes Berg
2020-10-09 8:03 ` Greg KH
2020-10-09 8:06 ` Johannes Berg
2020-10-09 8:16 ` Greg KH
2020-10-09 8:19 ` Johannes Berg
2020-10-09 8:34 ` David Laight
2020-10-09 8:44 ` Johannes Berg
2020-10-09 9:00 ` David Laight
2020-10-09 8:47 ` Greg KH
2020-10-09 8:48 ` Johannes Berg
2020-10-10 9:38 ` Greg KH
2020-10-10 10:47 ` Johannes Berg
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